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JAKE TAPPER, CNN HOST: Welcome back to THE LEAD. I'm Jake Tapper. The national lead. Which sounds more miserable to you? Thirty degrees and sheets of ice outside or darkness and no heat inside? Those are the options facing hundreds of thousands of families, thanks to a mix of ice, snow, and freezing rainmaking its way across the Midwest and northeast.

Nearly a million people are without power in Pennsylvania, New Jersey, and Maryland. The bulk of the outages are in the Philadelphia area where ice is bringing down trees and power lines. Pennsylvania now has 685 members of the National Guard on standby to help. In New York, the storm is being treated as a triple threat.

Governor Andrew Cuomo has already declared a state of emergency blaming a salt shortage for the unsafe roads in some parts of the state. Even areas used to getting hit with winters raft (ph) are having a tough time dealing with the sleet and ice. In Illinois, cars that couldn't be pushed off the road ended up stranded on the highway.

And if you're not in one of the areas being crippled by the winter weather, you can still feel the impact. According to Flight Aware, more than 2,700 flights have been canceled within, into, or out of the United States.

We have a team of reporters covering this nasty storm system. Ted Rowlands is braving the elements in Chicago, meteorologist, Jennifer Gray, has the latest on where the system is moving. But let's begin with our Don Lemon who is live in Boston. Don, how much snow are they digging out from where you are?

DON LEMON, CNN CORRESPONDENT: I'll show you, Jake. Thirty-three, by the way, feels like 22 here. And the best -- everyone is saying about anywhere from four to eight inches. I think it's a little bit more. This shows you just how deep it is. So, that looks like almost a foot of snow. A lot of shovels out today, a lot of salt, a lot of equipment out. There's some equipment roaming around, maybe during this live show (ph) you will get to see it.

As a matter of fact, one of the trucks, they got some of the -- they're not even going with sand here. They're going with straight salt to try to get all of this off the road. But as you said, about 120 million people affected by this, a million people still without power right now, 2,700 flights have been canceled all over the northeast.

And Maryland and Pennsylvania and New Jersey, a lot of people without power. They're really heavily affected by this. But this is Boston as you know, Jake. They're used to dealing with this. But again, they're trying to get all this stuff out on the road. A second wave is coming through and they're trying to deal with that. There was a lull for a little bit. First, it was very powdery, and now, it's turning into ice and that's going to be a problem. That's it for me here. I want to go to Ted Rowlands now, my colleague, who is in Chicago.

TED ROWLANDS, CNN CORRESPONDENT: Hey, thanks, Don. We're actually in Oak Park, Illinois just outside of Chicago. And this is a perfect example of the salt you were talking about and Jake was talking about earlier where they're running low. They're running low here in Oak Park. So, this is a side street. They did not salt it. You can see that there is snow on the street.

We're expecting temperatures to get down to about zero tonight, meaning, what is on the street right now will turn to a sheet of ice as the temperatures go down. People are being warned to really watch it in these suburban areas actually around the country where salt shortages have hit and communities are now just salting main thoroughfares.

You see the sidewalks have been salted. They're clear as can be. Let's head over to Jennifer Gray. She is in the CNN Weather Center in Atlanta. And hopefully, Jennifer, you're going to tell us that winter's over.

JENNIFER GRAY, AMS METEOROLOGIST: I wish I could say winter is over, but luckily, this storm system is close to being over. So, that will help a little bit. Boston still getting some of that snow. It has cleared out in providence all the way back to New York City and Philly. So, looking better as we go into the nighttime hours. Winter storm warnings still in effect for Boston, Albany.

We still have a winter weather advisory for New York, so it has dropped its winter storm warning just in the past hour or so. We are looking at maybe another inch or so of snow in Boston. Maybe two to four inches as you head into portions of Maine. But this will slowly be tapering off as we go into the overnight hours. The big story overnight will be the temperatures, because we're above freezing in some areas like New York City and even Philly.

So, what we are going getting a lilt bit of that melting going on, on the streets, the roadways, is becoming very slushy. That could all freeze overnight. So, we're going to have an icy problem as we head to our morning commute. The other big story, look at these temperatures. In Kansas, Nebraska, we're seeing temperatures in the single digits overnight. So, these are going to be some very, very cold temperatures waking up tomorrow morning, Jake.

TAPPER: All right. Jennifer Gray, Ted Rowlands, Don Lemon, thank you so much. Stay warm. When we come back, only two days until the opening ceremony of the Olympics, and Russia is still not done building. And now, a majority of Americans are saying they think a terrorist attack at the event is likely.

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TAPPER: Some breaking news now on THE LEAD, the Department of Homeland Security has just issued a warning for airlines flying to the winter Olympic Games in Sochi, Russia. Our justice reporter, Evan Perez, joins us now with the information. Evan, what can you tell us?

EVAN PEREZ, CNN JUSTICE REPORTER: Well, Jake, the Department of Homeland Security is clearly worried. The intelligence is showing that, you know, there are certain activities that clearly is causing some worry about the safety of flights that are going into Russia.

So, they've issued this directive to airlines that are traveling into Russia to be on the lookout for toothpaste tubes, cosmetic cases for the possibility that there could be bomb components that could be used to, you know, explode -- to explode a bomb on an airplane. So, it's something that they're clearly worried about.

It's not anything specific to the U.S. per se. There's no concern about something going on here. It's more something directed at Russia with the Olympic games about to get started over there.

TAPPER: So, the director of the National Counterterrorism Center, Mr. Olson, testified before Congress earlier this week and he said when asked about threats to the Olympic games said that there were a number of different threats of varying degrees of credibility that they were monitoring. Presumably, this probably was one of them and they obviously consider it to be credible.

PEREZ: Right. Exactly. And, you know, one of the things he said was they're working with the Russians to try to disrupt certain threats that they have seen going on. Now, we know from talking to officials that there's increased chatter, which is something that they expected given the Olympics about to start. So, this is -- seems to be an urgent reaction to something that they have seen, that they're clearly worried about, which threatens, you know, air travel into Russia in the next couple weeks.

TAPPER: And how was this alert distributed? Was it -- I mean, was this -- did you find out about this because they were shared with the public, with reporters, or airlines?

PEREZ: Well, it was shared with the airlines because the airlines are obviously getting ready. They want to know what the latest security information is. And obviously, as you know, I mean, you know, for the last few years, we've been making sure we put little bottles of liquid, you know, in our carry-on cases. And so, that's always been something that they've been worried about as far as the safety of air travel.

In this case, it seems to be that they're particularly worried about toothpaste tubes and cosmetic cases, which is -- which are things that they believe could be used to secrete some kind of, you know, materials to make a bomb to blow up an airplane.

TAPPER: Yes, because an obvious hole in the strategy of not allowing liquids above a certain amount -- a certain size is you just get four people on an airplane and each one of them has something that's allowable size, say, two and half ounces.

PEREZ: Right, exctly.

TAPPER: All of a sudden, you have ten ounces of whatever. Evan Perez, thank you so much.

Joining me now to talk about this and other issues, Mark Landler White House correspondent for "The New York Times" and Michelle Dunne, senior associate at the Carnegie Endowment for International Peace and former Middle East specialist at the state department.

So, obviously, this is breaking news, and we don't know much more about it than what Evan just said. But it has been a big issue, security, at the Sochi Olympics. And when you listen to what President Obama told me last week and what secretary of state, John Kerry, told me today, what I'm sure government officials have been telling you, there is not a rousing, go to the Olympics, you'll be safe.

It's go to Olympics and you'll be as safe as can be expected at a very large sporting event right near a war where there are lots of terrorist threats. Take precautions. I don't -- I supposed this is the new age, and it's good to have honest answers, but it's not reassuring.

MARK LANDLER, WHITE HOUSE CORRESPONDENT, THE NEW YORK TIMES: Right. And Jake, the last thing you said is sort of the critical thing. There's always going to be risk attached to large crowds regardless of whether the Olympics are in Sochi or in Atlanta as we sadly remember.

The difference here is the proximity of Sochi to the Caucasus, which is a sort of a hotbed of Islamic militancy and a place where in a number of these Caucas republics are actually fighting a low-grade civil war.

And so, you know, before we knew about this threat, which is clearly an external threat, planes going into Russia, one of the things that a lot of counterterrorism experts were talking about was less the idea that there would be a terrorist attack at the Olympics, which is a heavily secured area, but somewhere adjacent to in one of these republics, maybe 100 miles away, 250 miles away, it wouldn't directly hit people at the games, but it would certainly rattle everybody and throw a pretty long shadow over the games.

And I think that's still a risk even aside from what you've just reported now.

TAPPER: Michelle, Bob Baer, the former CIA officer, said that he thinks that the Islamic militants in this part of the world, the Caucasus, Dagestan, et cetera, are actually more serious and more of a threat in many ways than al Qaeda. The United States Has not paid -- the public has not paid a lot of attention to this region of the world. Who are these people? What are they fighting with the Russian government about?

MICHELLE DUNNE, SR. ASSOCIATE CARNEGIE ENDOWMENT: Well, there's a long history here of, you know, of Muslims in that part of the world and, you know, problems with Russia and the Soviet Union and so forth. But I think, you know, this is part of a bigger issue. I think there's a resurgence also of al Qaeda. I mean, the United States hasn't paid that much attention to those kind of extremists because they haven't targeted us, whereas, of course, al Qaeda did.

But I think that with what has gone on in Syria and even what's going on elsewhere in the Middle East, in Egypt, for example, we're seeing a real resurgence of Islamic extremism and of groups affiliated to al Qaeda and that could pose a danger to Americans as well.

TAPPER: I will say, though, there is still so much we don't know about the Boston marathon terrorist attack. Tamerlan Tsarnaev seems to have possibly been trained in Dagestan. But there's still much we don't know. We know he met with individuals who were later killed, I believe, by the Russians. So, it's not as though -- there isn't a direct line that we've established yet, but it's possible that this Caucasus terrorism has actually struck the United States in a way.

We're just not 100 percent clear yet. According to a new CNN poll, almost six in 10 Americans think that there will be an attack at the games. Now, Michelle, on the heel of this news, do you think Secretary Kerry, in his response to me earlier today, was being overly optimistic or do you think that's the right tone?

You know, I wouldn't discourage anybody from going but just be as aware as you would be if you were going, say, this is my words, not his, but to the Super Bowl.

DUNNE: Well, I'm sure Secretary Kerry doesn't want to be seen and doesn't want the United States to be seen as somehow undermining, you know, these Olympics or undermining Russia and its leadership for whom these Olympics are, you know, a big issue. At the same time, though, he certainly did talk more about all the things that we're doing to cooperate, to make the security as good as it could be.

And he didn't talk as much about the threat. And I agree with what Mark said. There's always a threat at these kinds of gatherings, but they're very specific threats this time, and that does make it, you know, a little more scary.

JAKE TAPPER, CNN HOST: This is a specific threat. For department of Homeland Security to tell airlines, knowing that the news would come to us and then we would inform the public, so to say be on the lookout for toothpaste tubes, we're worried about a bomb on an airplane going into Russia, that means that -- explain it.

MARK LANDLER, WHITE HOUSE CORRESPONDENT, "THE NEW YORK TIMES": I think the protocol for a threat warning of that kind is that they had something specific that they're responding to. They're not making any kind of a general blanket warning. In fact, prior to what you just reported, that was a very classic way of handling sort of a generalized risk environment, to say that people should be careful when you they are in crowds. But to issue a threat to airlines is a very different thing. It probably requires much tighter TSA security procedures on flights or other security procedures on flights headed into Russia. So yes, there's probably likely something specific, tangible that they're responding to.

TAPPER: Mark and Michele, stay with us. We're going to take a very quick break. Much more on this breaking news after this.

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TAPPER: Welcome back to THE LEAD. We're following some breaking news for concerning the Winter Olympic Games scheduled to kick off just a few days from. The Department of Homeland Security is warning airlines flying to Russia to be on the lookout for explosives possibly in the tubes of toothpaste.

Joining us now on the phone from Denver, CNN law enforcement analyst, Tom Fuentes. Tom, have you heard of this kind of threat before, materials in toothpaste, especially recently?

TOM FUENTES, CNN LAW ENFORCEMENT ANALYST (via telephone): Well not so much recently, Jake, but there's been concern in the past that toothpaste or other -- whether it's contact lens solution or other devices could be used actually to insert some type of an explosive device or some type of a poison into it. But it's not brand new, but it's nothing used recently.

TAPPER: You used to be a top official at the FBI. Is it your impression from what you know they are concerned about these explosives and toothpaste tubes because the terrorists would use the explosives on the airplane or is it possible that this is just importation of explosives into Sochi?

FUENTES: Yes. I think the greater concern is that it would be taken into sochi and that it could be taken in checked-in luggage as opposed to carry-on. We know there's a grouping for carry-on luggage, especially for flights connecting to go into Sochi, but people would obviously have their toiletries in their checked luggage and, you know, you already have people that have travelled there. So even putting the warning out now and alerting the Russians to be extra vigilant, it's going to mean for them to not only remove toothpastes from carry-ons but from checked luggage.

TAPPER: Obviously we're talking about people smuggling explosives in toothpaste tubes. Would that be that difficult to process to do? Hide an explosive, not a device, I suppose, but an explosive powder, an explosive liquid in a toothpaste tube, put it in your checked baggage and take it anywhere you want to take it?

FUENTES: No, it would not. The threats over the years, the terrorists were going to insert explosives in shaving cream or other liquids, baby formula, you name it, and that's caused searches and of course that threat dies down far while and we don't hear too much about it. But, you know, since 9/11, we have many different plots involved inserting some type of a liquid onto the plane.

Most of those involved having it in carry-on luggage, what you would take on the plane and be able to try to detonate it yourself like the shoe bomber or the underwear bomber. But in this case, they would take it into Sochi and then have it during the next couple weeks while the Olympics are ongoing.

So it's not so much the threat alone for the aircraft, but if the material is already there, that's on top of the fact that the terrorists have had seven years to move whatever contra band, whether it's explosives, firearms, detonators, paraphernalia, they've had a long time to stash material like that in Sochi before the ring of steel was ever created.

TAPPER: All right, Tom Fuentes, stay with us. We're going to take another quick break. We come back more on this breaking news about a warning from the Department of Homeland Security about terrorists possibly trying to smuggle explosives in toothpaste tubes onto airplanes on planes bound for Russia. We'll be right back.

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BARACK OBAMA, PRESIDENT OF THE UNITED STATES OF AMERICA: I tell them that I believe that Sochi is safe and that there are always some risks in these large international gatherings. I'm always going to feel even better if it's inside the United States because then we have full control over what happens. But the Russian authorities understand the stakes here. They understand that there are potential threats that are out there, and we are coordinating with them.

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TAPPER: Welcome back to THE LEAD. We're following some breaking news for you, a terror alert ahead of the Winter Olympic Games scheduled to kick off just two days from now. The Department of Homeland Security is warning airlines flying to Russia to be on the lookout for explosives, possibly explosives being concealed in toothpaste tubes.

Let's go right to our senior international correspondent, Nick Paton Walsh. He is live in Sochi, Russia. Nick, what's the history of explosives on planes in Russia?

NICK PATON WALSH, CNN SENIOR INTERNATIONAL CORRESPONDENT: It had a long history of it here. Back in 2004 before the hostage crisis there were two simultaneous explosions that bombed two separate airliners, which took them out of the sky. There were both female suicide bombers behind those blasts and a lot of the rumors afterwards were perhaps they got on board by using face cream tub, large ones.

This is before the restrictions of 100 millilitres that now plague most of us with our hand luggage. One other important point, Jake, too, is that we're now seeing a complete ban on liquids in hand luggage across Russia. The planes we took here wouldn't let you take anything on board at all, not even 100 millilitres worth.

So clearly the Russians are concerned about something. They were the first to introduce those full-body scanners you see at airplanes after those 2004 blasts. So definitely concerns here. They've tried to pre-empt them, but this is borne of a long history of uncertainty. They're probably not using toothpaste tubes to bring explosives here. It's probably something they would like to attempt in the air -- Jake.

TAPPER: Nick Paton Walsh, thank you so much. That is one theory. Of course another theory from a former FBI agent we just spoke with is that the explosives would be smuggled into Russia, into Sochi to wreak havoc there. There is much of the story we do not know. Our coverage of this breaking continues with Wolf Blitzer. He is in "THE SITUATION ROOM." Mr. Blitzer, take it away.